/**
 * Software License, Version 1.0
 * 
 * Copyright 2008 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgment:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgment may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or Granules, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called Granules, 
 * nor may Indiana University or Community Grids Lab or Granules appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 * LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 * WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 * NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 * INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 * INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 * "VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 * LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 * ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 * GENERATED USING SOFTWARE.
 */
package cgl.granules.util;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Properties;

import cgl.granules.exception.DeploymentException;

/**
 * This is a utility class which is useful in reading specified configuration
 * parameters.
 * 
 * @author Shrideep Pallickara
 * 
 */

public class ParamsReader {

    private static final ParamsReader instance = new ParamsReader();


    private ParamsReader() {
    }


    /**
     * Retrieve the instance of the Params-Reader
     * 
     * @return The singleton instance.
     */
    public static ParamsReader getInstance() {
        return instance;
    }


    /**
     * Constructs a set of properties from the specified configuration file. The
     * properties in the file would be specified as a set of property=value
     * entries.
     * 
     * @param configFileLocation
     *            The location of the configuration file.
     * @return The constructed properties
     * @throws DeploymentException
     *             If there are problems constructing the properties.
     */
    public Properties getProperties(String configFileLocation)
        throws DeploymentException {
        if (configFileLocation == null) {
            throw new NullPointerException("Specified configuration file "
                + "location is null.");
        }

        File configFile = new File(configFileLocation);
        Properties properties = new Properties();
        FileInputStream fis;

        if (!configFile.exists()) {
            String errorReport =
                "Unable to locate file: " + configFile.getAbsolutePath();
            throwDeploymentException(errorReport);
        }

        try {
            fis = new FileInputStream(configFile);
            properties.load(fis);
            //System.out.println(properties);
        } catch (FileNotFoundException e) {
            String errorReport =
                "Unable to create FileInputStream because file"
                    + configFile.getAbsolutePath() + " does not exist. "
                    + e.getMessage();
            throwDeploymentException(errorReport);
        } catch (IOException e) {
            String errorReport =
                "Problems reconstructing Property-List from " + " file: "
                    + configFile.getAbsolutePath();
            throwDeploymentException(errorReport);
        }

        return properties;
    }


    private void throwDeploymentException(String errorReport)
        throws DeploymentException {
        throw new DeploymentException(errorReport);
    }
}
